#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
#include <ctime>
using namespace std;

char buff[1000];

int main(){
    int t;
    scanf("%d", &t);
    while(t--){
        int n,m;
        scanf("%d%d", &n, &m);
        vector<int> a(m);
        for(int i=0; i<m; i++){
            scanf("%d", &a[i]);
        }
        a.push_back(-1);
        a.push_back(n);
        sort(a.begin(), a.end());

        vector<double> dp(n+1, 0);
        for(int i=1; i<=m; i++){
            //vector<double> dp_(n+1, 0);
            for(int l=a[i-1]+1; l<=(i==1?0:a[i]); l++){
                for(int r=(i==m?n:a[i]+1); r<=a[i+1]; r++){
                    dp[r] = max(dp[r], log2(r-l)+dp[l]);
                }
            }
            //swap(dp, dp_);
        }

        printf("%I64d\n", (long long)(floor(dp[n]*1000000)) );
    }
    return 0;
}